In A Nutshell

Despite fighting on the same side as Britain at the end of World War I, in the 1920s and ’30s the US drew up several plans for wars against other countries—even the British Empire. The plan included an invasion of Canada, use of chemical weapons, and a naval blockade of Britain herself. The scenario that would have led to war was predicted to come about due to a trade disagreement. If the plan had gone ahead, US troops would have occupied any colonies captured in the event of a peace agreement.

The Whole Bushel

Despite years of hostility and warfare between the two nations, the US and the British Empire ended up fighting side by side against the German army at the end of World War I. This didn’t stop the US from making a backup plan afterward, though. Named “War Plan Red” (with plans for war against other countries named after other colors), the main aim was to remove Britain from her status as a world superpower. (Relations between the two countries weren’t helped at the time by the fact that Britain owed the depression-hit US $14 billion in wartime loans.) The plan was approved in 1930 and was active until the start of World War II.

And in case you thought it was just war gaming, it was the only war plan to receive funding during this time period. The money was spent on airfields along the Canadian border, to the tune of $1 billion in today’s money.

Among the concerns the American planners faced was the might of the Royal Navy, the manpower the British could draw from its colonies around the world, and (of course) America’s neighbor Canada, which at the time was still strongly influenced by Britain. In the event of war, Canada would provide a useful base for an overland or amphibious attack for British forces on America.

The initial step in the American plan was to invade Canada, first heading for Halifax to capture the vital port situated there and prevent it being used to land reinforcements. American troops would also attack Montreal, Quebec City, Ontario, and Manitoba in an attempt to stop the Canadian movement of troops to repel the invasion. A naval blockade would have been put in place to keep the British out of the fight. There were also plans to use chemical weapons, akin to the horrors in the trenches of the First World War. This would have violated the Geneva Convention and amounted to a war crime.

Even with all that, a quick victory was not expected. As noted by the planners, Britain certainly had the “ability to fight to a finish.” Although there were no plans to attack the British Isles themselves, an American conquest of Canada and other British bases in the North Atlantic would have severely crippled Britain economically, thus reducing her reach. As a result, Britain’s role as a superpower would have diminished prematurely, potentially losing control of many of her colonies and possibly negatively affecting the outcome of World War II.

Had a peace agreement been reached after War Plan Red was in action, the American planners had designated any areas occupied by American troops “blue,” meaning they were to become part of the US, possibly including Caribbean islands such as Jamaica. This would have prevented a possible British future build-up to resume hostilities.

We’ll never know how this would have ended, but a war between the two superpowers a few years before Hitler’s rise and Japan’s Asian expansion could have allowed the two future Axis nations to conquer whatever they pleased. The British and American economies would have been damaged massively, diminishing their respective abilities to stop Nazi Germany and Imperial Japan. The outcome for the world could have been terrifying.